Since astronomers first measured the size of an extrasolar planet 17 years ago, they have struggled to answer the question: how did the largest planets get to be so large?

Since astronomers first measured the size of an extrasolar planet 17 years ago, they have struggled to answer the question: how did the largest planets get to be so large?
A whole set of carefully constructed models have been abandoned due to the 400 light-year distant CW Leonis’ odd behaviour